Prevalence and characteristics of the aortic ejection sound in adults.

A survey of 1,950 phonocardiograms recorded over a 6-year period revealed 170 (9%) with a distinct aortic ejection sound. All patients were men with a mean age of 61 years (range 29 to 88). Associated clinical features were: aortic stenosis in 28%, history of systemic hypertension in 10%, history of rheumatic fever in 4% and none of these features in 58% of patients. In 141 (83%) of 170 patients the aortic ejection sound occurred simultaneously with or 0.01 second before or after the onset of the rise of the externally recorded carotid pulse. In 37 (66%) of 56 patients who had simultaneous echocardiograms and phonocardiograms recorded, the aortic ejection sound occurred at 0.01 second before or after the maximal opening point of the aortic valve leaflets. Two-dimensional echocardiography was performed in all patients and a bicuspid aortic valve was identified in 38 patients (22%). In 83 patients (49%) 3 cusps were clearly seen. In 49 patients (29%) an accurate determination was not possible. Anatomic examination of 120 consecutive aortic valves at autopsy was performed to identify possible causes of the aortic ejection sound. In 18 (15%) of autopsies fusion of 2 aortic cusps extending greater than or equal to 5 mm from the attachment to the aorta was observed. This abnormality, aortic commissural fusion, may be congenital or acquired. It is concluded that aortic ejection sounds may occur in patients without bicuspid aortic valves and in a variety of clinical conditions. A moderate degree of cuspal fusion may be the cause of the sound.